A4VSO500DRG/30L-PPB13N00 German made Rexroth original piston hydraulic pump

FAQ — Frequently Asked Questions

Q1: What does "DRG" control mean and how is it different from plain "DR"?

A:​

• DR​ = Pressure compensator with local mechanical adjustment only.

• DRG​ = Same pressure compensator plus a pilot port (X)​ allowing remote pressure setting/modulation​ via an external pilot reducing valve or proportional valve, while still keeping the local adjustment screw as a max/official setting. Useful when you need to change the pump's pressure setpoint electrically/pneumatically from a distance.

Q2: The rotation code is "L" (30L) — what does that mean practically?

A:​ "L" = Counter-Clockwise​ when viewed from the drive shaft end. This is the opposite of the more common "R" (Clockwise). The pump must be driven in this direction​ — running it in reverse will cause immediate failure due to loss of lubrication and improper suction. Always verify your prime mover / coupling rotates counter-clockwise from the shaft side.

Q3: What are the suction (inlet) requirements for this 500 cc pump?

A:​ With 500 cm³/rev displacement, inlet conditions are critical:

• At 1200 rpm, inlet absolute pressure should be ≥ 1.0–1.2 bar​ (boost pump strongly recommended for sustained high-speed operation).

• For speeds >1200 rpm, a dedicated charge pump / supercharge circuit​ is essential to prevent cavitation.

• Use generously sized inlet piping (≥ DN80/100), minimize elbows/restrictions, and fit a 149 µm (100 mesh) suction strainer.

Q4: Can I mount an auxiliary pump (gear pump) on the rear?

A:​ No.​ The suffix N00​ indicates no through-drive shaft. The rear of the pump housing is blanked. If you need a through-drive for a charge / pilot gear pump, select a version with a through-drive code such as K01, K02, etc.

Q5: How should the case drain (L port) be handled?

A:​ Connect one case drain port​ directly to the tank with a dedicated line — zero backpressure​ (max 0.5 bar). The second drain port must be plugged. Route the drain line to above the tank oil level or provide a loop to prevent air ingestion. A blocked or pressurized drain = shaft seal failure.

Q6: What drive motor power is required?

A:​ At 1200 rpm, 350 bar, and 500 cc:

• Theoretical hydraulic power ≈ (500 × 10⁻⁶ × 350 × 1200) / 600 ≈ 350 kW

• Including mechanical losses (~90%), input power ≈ 390 kW

  Recommend a 400 kW (≈535 HP)​ prime mover with adequate starting torque reserve for 400 bar peak conditions.

Q7: Is the standard NBR seal okay for water glycol (HFC) or phosphate ester (HFD)?

A:​ Standard NBR is compatible with HFC (water glycol) with pressure/temp derating. It is NOT compatible with HFD (phosphate ester)​ — for HFD you need FKM (Viton) seals, typically a custom order with /V suffix. Confirm with Rexroth if your fluid is not mineral oil (HL/HLP).